Refrigerating machine



7 Inventor: Delbert F Newman.

His Attovngg.

D. F. NEWMAN REFRIGERATING MACHINE Filed Feb. 1'7, 1937 Fllll Jul -s,1938.

Patented July 5,1938

REFRIGERATING MACHINE Delbert F. Newman, Schenectady, N. Y., asslgnor toGeneral Electric Comp ny. a corporation of New York Application February17, 1931, Serial No. 126,211

Claims.

high temperature of the evaporator during the initial portion of the"pull-down period, the

gaseous refrigerant drawn into the compressor and discharged into thecondenser has a density considerably higher than normal, resulting inthe compressor handling a much larger quantity of gaseous refrigerantthan under normal operating conditions. The condenser is designed tocondense only the gaseous refrigerant at the normal rate of dischargefrom the compressor, in order to provide an economical construction. Themachine is, therefore, incapable of condensing the gaseous refrigerantat this increased rate of discharge from the compressor during theinitial portion of this period, causing an abnormally high pressure toexist in the condenser. The compressor discharging against thisabnormally high pressure head in the condenser may cause the motordriving the compressor to become overloaded or stalled.

It is an object of my invention to provide a compression typerefrigerating machine having an arrangement for minimizing the increasein pressure above normal of the compressed refrigerant in the machineduring the pull-down period of an evaporator associated with the machinefrom substantially an ambient temperature to an operating coolingtemperature in order to prevent overloading of the compressor drivingmotor. I accomplish this by utilizing a refrigerant cooler interposed inthe high pressure refrigerant circuit of the machine between thecompressor and the condenser, the refrigerant cooler being arranged ingood heat' exchange relationship with a heat absorbing body. Preferably,the refrigerant cooler is arranged in good heat exchange relationshipwith an hermetically sealed casing enclosing the compressor and itselectric driving motor in order to provide a compact machine.

Further objects and advantages of my invention will become apparent asthe following dewhich characterize my invention will be pointed out withparticularity in the claims annexed to and forming a part of thisspecification.

For a better understanding of my invention, reference may be had to theaccompany drawing, in which Fig. 1 is a side elevation of a refrigeratorcabinet provided with a refrigerating machine embodying my invention,portions of the cabinet and machine being broken away to show moreclearly the arrangement; and Fig. 2 is an enlarged fragmentary sectionalview of the enclosing casing for the compressor and its driving motorand the refrigerant cooler arranged in good heat exchange relationshiptherewith.

Referring to the drawing, in Fig. 1 I have shown a refrigerator cabinetl0 designed for domestic use which is provided with a heat insulatedfood storage compartment H in the upper portion thereof and a machinerycompartment l2 arranged below the compartment H. An opening is formed inthe front wall of the compartment H to afford access to the interior ofthe compartment and a heat insulated door I 3 is hinged adjacent themarginal edge of this opening. Openings are formed in both the front andrear walls of the machinery compartment l2 to afford ready access to therefrigerating machine arranged therein for purposes of inspection. Aremovable door I4 is arranged tocover the opening in the front wall ofthe ma.- chinery compartment l2 in order to give the refrigeratorcabinet a finished appearance.

The refrigerating machine includes a cylindrical hermetically sealedcasing l5 in which an electric driving motor l6 and a refrigerantcompressor l1 are arranged, the compressor being secured to the top ofthe motor. Preferably, the casing I5 is constructed of sheet steel andhas a relatively large mass. The motor and the compressor areresiliently mounted in the casing l5 on a series of equally spacedhelical compression springs 18. The upper ends of the springs l8 aresecured to the frame of the motor I 6 by a number of supporting feet l9and the lower ends of the springs iii are secured to the bottom wall orend of the casing IS. The

springs l8 permit the motor and the compressor portion thereof which isrecirculated to the moving parts of the motor and the compressor duringthe operation of the machine.

The casing I I is substantially vertically disposed and is secured to asupporting frame 20 adjacent the rear of the machinery compartment II.An air distributing hood 23 is secured to the supporting frame 23adjacent the front of the machinery compartment l2 and is provided withan air inlet opening arranged in the front and bottom walls thereof foradmitting cooling air into the machinery compartment below and adjacentthe door II. The upper portion of the hood I! is securely braced by astrap 30 fastened to the casing II. An air outlet opening 3| is formedin the wall of the hood 2! adjacent the casing II and a fan 31 isarranged in the opening 3| in order to draw the cooling air through thehood. The fan 32 is operated by an electric motor 33 supported upon thecasing I! by a brack et II. Within the hood 23 and adjacent the outletopening 3l there is arranged an annular frustro-conical air deflectingbaille 33 supported upon a series of studs 33. The cooling air drawninto the hood 23 by the fan 33 is distributed uniformly through the hoodby the air deflecting baille 33 and is discharged through the outletopening 3|. The baffle 33 also contributes toward quiet operation of thefan 33 by distributing the cooling air drawn through the hood 23 moreuniformly adjacent the outlet opening 3 I.

During operation 01' the refrigerating machine illustrated, gaseousrefrigerant is drawn into the compressor II from the casing 15 throughan intake mufller 31 and is compressed and discharged into an exhaustmufller 38. the intake and exhaust mumers being arranged within theenclosing casing IS. The compressed gaseous refrigerant is conductedfrom the exhaust mumer 33 by a flexible conduit 39 into a conduit 40arranged exteriorly of the casing." and sealed in an opening in thebottom of the casing ii. The conduit 30 communicates with a refrigerantcooler ll disposed in good heat exchange relationship with the lowerportion of the casing II. This casing is formed of sheet steel and has arelatively large mass constituting a heat absorbing body. Preferably,the refrigerant cooler ll comprises a coil of copper pipe having asubstantially half-round cross section, the flattened wall a of the coilbeing soldered to the periphery of the casing II as shown at llb in Fig.2. The com pressed refrigerant, after passing through the cooler II. isconducted by a conduit 42 into the upper portion of a refrigerantcondenser 43, the condenser 43 being arranged within the airdistributing hood 23 adjacent the inlet opening in the front and bottomwalls of the hood. The condenser 43 is arranged in an inclined positionto facilitate the flow of the refrigerant liquefied therein in adownward direction and is secured in place upon a wall of the hood 23 bybolts 44. The compressed refrigerant is liquefied in the condenser 43and flows from the lower portion thereof through a liquid conduit 45into a suitable flow controlling float valve 43 arranged in the top ofthe cabinet, which regulates the quantity of liquid refrigerant suppliedthrough a conduit 41 to a flooded type sheet metal evaporator 43. Theevaporator 33 is positioned in the upper portion of the food storagecompartment II and is suspended beneath the top wall thereof. The liquidrefrigerant contained in the evaporator 33 is vaporized by theabsorption of heat from articles contained in the compartment in whichthe evaporator is located and the vaporized refrigerant is collected ina cylindrical header 43 which is normally maintained about one-half fullof liquid refrigerant The vaporized gaseous refrigerant accumulating inthe upper portion of the header 2! above the level of the liquidrefrigerant therein is conducted through a conduit ll into a cofl 5|arranged in good heat exchange relationship with a tubular extension onthe flow controlling float valve 43 in order to cool the liquidrefrigerant supplied to the evaporator ll. The gaseous refrigerant isthen returned to the interior of the casing II through a suction conduit32. It will be noted that the discharge end 52a of the suction conduit62 is located above the level of the body of lubricant contained in thelower portion of the casing II. The gaseous refrigerant thus dischargedinto the casing II is again drawn into the compressor l1 through theintake muiller 31 and the cycle above described is repeated until thefood storage compartment II in which the evaporator 40 is located iscooled to the desired temperature. Preferably. the liquid conduit 43 andthe suction conduit 52 are arranged in a flexible enclosing conduit 53extending from the machinery compartment I2 up the rear wall of therefrigerator cabinet to the upper portion of the cabinet II.

The supporting arrangement for the enclosing casing ll and the airdistributing hood 2! permits the refrigerating machine to be readilyplaced into and removed from the machinery compartment I! in assembledrelation without disturbing the evaporator 43 in the food storagecompartment ll.

During operation of the refrigerating machine, cooling air is drawn intothe air distributing hood 29 by the fan 32 through the inlet opening inthe front and bottom walls thereof below and adjacent the door llclosing the opening in the front wall of the machinery compartment. Thecooling air then flows uniformly through the refrigerant condenser 43due to the arrangement of the air deflecting baflle 35 and is dischargedthrough the outlet opening 3| about the casing II and the refrigerantcooler II. The cooling air flows about the casing and refrigerant coolerand out of the machinery compartment through the opening in the rearwall of the compartment. Preferably, the fan driving motor 33 isarranged in a circuit with the compressor driving motor i3 and asuitable thermal control device which is operable to maintain any givenaverage temperature over a predetermined range of temperatures withinthe food storage compartment ll, so that these motors are started andstopped simultaneously.

During the initial portion of the pull-down" period the gaseousrefrigerant drawn into the compressor I! from the enclosing casing I!has a density considerably higher than normal due to the relatively hightemperature of the evaporator 48. Consequently, the compressor handles amuch larger quantity of gaseous refrigerant during the initial portionof the pull-down" period than under normal operating conditions. Thecondenser 43 is designed to condense only the gaseous refrigerant at thenormal rate of discharge from the compressor in order to provide aneconomical construction. Thus, the machine is incapable of condensingthe gaseous refrigerant at this increased rate of discharge from thecompressor during the initial portion of this period. It is apparentthat if the compressor I! were arranged to discharge directly into thecondenser 43, an abnormally high pressure would be built up in thecondenser 43 during the initial portion of the pull-down period and that.head would overload the compressor driving motor ii. In fact, thedriving motor i6 might become so heavily overloaded that it would becomestalled.

In order to minimize abnormally high pressures in the refrigeratingmachine during the initial portion of the pull-down" period, therefrigerant cooler 4i is arranged in good heat exchange relationshipwith the casing I5 and is interposed in the high pressure circuit of therefrigerating machine between the compressor l1 and the condenser 43.All of the elements of the refrigerating machine including the casing I!have a tempera-- ture corresponding to ambient at the beginning of thepull-down period as previously pointed out, which temperature isconsiderably lower than the temperature of the compressed gaseousrefrigerant discharged from the compressor. The casing I 5 beingconstructed of sheet steel and having a relatively large mass, thus hasa considerable capacity for absorbing heat from the refrigerant cooler4i and the compressed gaseous refrigerant passing through the coolerduring the initial portion of the pull-down"period. The cooling actionof the refrigerant cooler 4i upon the compressed gaseous refrigerantpassing therethrough and entering the condenser 43 reduces the amount ofsuperheat of the compressed gaseous refrigerant and remains the samewhenit reaches the condenser 43, permitting the compressed gaseousrefrigerant to be readily liquefied in the condenser at a relatively lowpressure and to be supplied to the evaporator 48. It will be noted thatthe resilient mounting of the compressor driving motor l6 including thehelical compression springs l8 spaces the motor within the enclosingcasing i5 away from the side walls thereof, which spacing retards theflow of heat from the motor to the casing. This mounting arrangementallows the refrigerant cooler 4| to utilize substantially all of theheat absorbing capacity of the casing l5 to cool thecompressed gaseousrefrigerant during the initial portion of the pull-down period.Consequently, the existence of abnormally high pressures in therefrigerating machine are minimized.

The temperature of the casing l5 gradually rises upon operation of themachine during the pull-down period due to the absorption of heat fromthe refrigerant cooler 41. The temperature of the casing approaches thetemperature of the refrigerant cooler, at which point no precooling ofthe compressed gaseous refrigerant is effected. In a similar manner, thedensity of the gaseous refrigerant drawn into the compressor I! from thecasing l5 gradually decreases during the operation of the machine due tothe lowering of the temperature of the evaporator 48, causing acorresponding gradual decrease in the rate of discharge of the gaseousrefrigerant from the compressor l1. Thus, the rate of discharge of thegaseous refrigerant from the compressor approaches normal, at whichpoint no pre-cooling of the compressed gaseous refrigerant is requiredby the condenser. From the above description of operation of therefrigerating machine, it will be understood that pre-cooling of thecompressed gaseous refrigerant is required only during the initialportion of the pull-down period to avoid abnormally high pressures inthe refrigerating machine, and that the refrigerant cooler is operableto effect pre-cooling of the compressed gaseous refrigerant during thisportion of the be understood that no pre-cooling of the compressedgaseous refrigerant is required during" the normal operation of therefrigerating machine as the condenser is capable of condensing thecompressed gaseous refrigerant at the normal rate of discharge from thecompressor, and that the refrigerant cooler effects no appreciablepre-cooling of the gaseous refrigerant during normal operation of therefrigerating machine.

It will thus be seen that I have provided a compression typerefrigerating machine having a compact arrangement for minimizing theincrease in pressure above normal-of the compressed refrigerant in themachine during the pull-down period of an evaporator associated with themachine from substantially an ambient temperature to an operatingcooling temperature.

While I have shown a particular embodiment of my invention in connectionwith a refrigerating machine designed for domestic use, I do not desiremy invention to be limited to the particular construction shown anddescribed, and I intend in the appended claims to cover allmodifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. A refrigerating machine including a refrigerant compressor, means fordriving said compressor, means including a condenser communicating withsaid compressor for liquefying the compressed refrigerant deliveredthereto, an

evaporator supplied with liquid refrigerant from said condenser, a heatabsorbing body, and means including a refrigerant cooler connectedbetween said compressor and said condenser and arranged in good heatexchange relationship with said heat absorbing body for minimizing theincrease in pressure above normal of the compressed refrigerant in therefrigerating machine during the pull-down period of said evaporatorfrom substantially an ambient temperature to an operating coolingtemperature, said last-mentioned means utilizing the heat absorbingcapacity of said body during the initial portion of the pulldown" periodfor reducing the amount of superheat of the compressed refrigerantdelivered to said condenser.

2. A refrigerating machine including a refrigerant compressor, a motorfor driving said compressor, a casing enclosing said compressor and saidmotor, means including a condenser communicating withsaid compressor forliquefying the compressed refrigerant delivered thereto, an evaporatorsupplied with liquid refrigerant from said condenser, and meansincluding a refrigerant cooler connected between said compressor andsaid condenser and arranged in good heat exchange relationship with saidcasing for minimizing the increase in pressure above normal ofthe'compressed refrigerant in the refrigerating machine during thepull-down period of said evaporator from substantially-an ambienttemperature to an operating cooling temperature, said last-mentionedmeans utilizing the heat absorbing capacity of said casing during theinitial portion of the pull-down period for reducing the amount ofsuperheat of the compressed refrigerant delivered to said condenser.

3. A refrigerating machine including a refrigerant compressor, a motorfor driving said compressor, a casing enclosing said compressor and saidmotor, means including a condenser communicating with said compressorfor liquefying the compressed refrigerant delivered thereto. anevaporator supplied with liquid refrigerant from said condenser. andmeans including a refrigerant cooler connected between said compressorand said condenser and arranged about said casing in good heat exchangerelationship therewith for preventing overloading oi said driving motorduring the "pull-down period" of said evaporator from substantially anambient temperature to an operative cooling temperature, saidlast-mentioned means utilising the heat ahsorhing capacity of saidcasing during the initial portion of the "pull-down" period for reducingthe amount of superheat oi the compressed refrigerant delivered to saidcondenser.

4. A refrigerating machine including a refrigerant compressor. a motorfor driving said compressor, a casing enclosing said compressor and saidmotor, means including a condenser communicating with said compressorfor liquefying the compressed refrigerant delivered thereto, anevaporator supplied with liquid refrigerant from said condenser, andmeans including a refrigerant cooler coil connected between saidcompressor and said condenser and arranged about said casing in goodheat exchange relationship therewith for minimizing the increase inpressure above normal of the compressed refrigerant in the refrigeratingmachine during the pulldown" period of said evaporator fromsubstantially an ambient temperature to an operative coolingtemperature, said last-mentioned means utilising the heat absorbingcapacity of said casing during the initial portion of the "pulldownperiod for reducing the amount of superheat of the compressedrefrigerant delivered to said condenser.

5. A refrigerating machine including a refrigerant compressor, a motorfor driving said compressor. a casing enclosing said compressor and saidmotor, means including a condenser communicating with said compressorfor liquefying the compressed refrigerant delivered thereto, anevaporator supplied with liquid refrigerant from said condenser, meansincluding a refrigerant cooler connected between said compressor andsaid condenser and arranged in good heat exchange relationship with saidcasing for minimizing the increase in pressure above normal of thecompressedrefrigerant in the refrigerating machine during the pull-down"period of said evaporator from substantially an ambient temperature toan operative cooling temperature, said last-mentioned means utilizingthe heat absorbing capacity of said casing during the initial portion ofthe pull-down" period for reducing the amount of superheat of thecompressed refrigerant delivered to said condenser, and means fordirecting a current of cooling air over said condenser and thence oversaid cooler and said casing;

DELBERT F. NEWMAN.

